because gamepass was the reason that the lineup was weak
. They didn't mind not having any games at launch for new hardware because they were too concerned with hours instead of concerned with selling consoles:
As the Xbox Series X and Series S are released, Microsoft gaming chief Phil Spencer says the next games generation is all about how many players you have, not how many consoles you shift
www.theguardian.com
They delayed games instead of spending more money ramping up development because they were still seeing gamepass growth at the time and that was beneficial to them. Delays meant revenue was coming from the sub every month while they worked on the game. Instead of spending more money for it to go into the sub quicker.